Magnesium Oxide Nanoparticles or Magnesia Nanoparticles (MgO) Nanoparticles, nanodots or nanopowder are spinel, high surface area particles. Nanoscale Magnesium Oxide Nanoparticles or Magnesia Particles are typically 5 - 100 nanometers (nm) with specific surface area (SSA) in the 25 - 50 m2/g range.